WIP: Remove custom parser in favor of another package

[baronfel]

This PR

• removes the fparsec-based Changelog parser
• migrates the task to C#
• Makes the ChangelogFile parameter no longer inferred, so users have to supply it

I did this because

• maintaining a parser is a pain, and not actually core to these tasks
• VS support for multi FSharp.Core references seems to be quite hard
• It makes this repo more readable for folks that don't know F#, so I can use it more as a template/example for prospective task authors

Current problems:

• [ ] the packaging isn't correct. When multitargeting the ResolveReferences target doesn't run when I expect and so no BuildOutputInPackage items are written for the net6.0 TFM. This results in the following incorrect package layout:

[baronfel]

Here we can see that GenerateNuspec is building the _GetBuildOutputfilesWithTfm target with a TFM set for both net472 and net6.0, as expected. My custom targets cause ResolveReferences to run, however only the net472 ResolveReferences is used?

[baronfel]

Rainer helped me figure out what was going on:

• no package references runtime files were being marked as CopyLocal, because there's a line in the SDK that defaults CopyLocalLockFileReferences to false unless you meet a condition. That condition is to set <EnableDynamicLoading>true</EnableDynamicLoading>.

This same property also results in deps.json files being generated, so we should just simplify to that property.

It's pretty cool that with that property, there's no difference in targeting Full framework vs .NET MSBuild, from a packaging perspective. Really sweet stuff.

The package itself needs testing (which I'll do manually now that the package is valid), but we're almost ready to merge this.

[albertwoo]

Any plan to merge this PR? I am facing below issue on VisualStudio 2022, but use dotnet cli is working as expected. I think this PR may solve my issue.

ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018: The "Ionide.KeepAChangelog.Tasks.ParseChangeLogs" task failed unexpectedly.
ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018: System.IO.FileNotFoundException: Could not load file or assembly 'FParsec, Version=1.1.1.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018: File name: 'FParsec, Version=1.1.1.0, Culture=neutral, PublicKeyToken=null'
ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018:    at KeepAChangelog.Tasks.ParseChangelogs.Execute()
ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
ionide.keepachangelog.tasks\0.1.8\build\Ionide.KeepAChangelog.Tasks.targets(29,9): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext()